Just weeks after Westpac's online banking systems were crippled by a Denial of Service (DoS) attack, it is warning customers about a new wave of hoax e-mails.

Australia's fourth largest bank on Wednesday published a warning on its Web site about a hoax e-mail that advises customers to view the bank's new Internet banking service terms and conditions. Users are encouraged to follow a link to the spoof site.

Westpac points out that while corporate branding in the e-mail appears to be legitimate, wording, grammar and spelling are poor.

Westpac advises customers to delete the e-mail from their Inbox and Deleted folder. It also recommends viewing the ASIC Web site.

Westpac's privacy and security statement guarantees customers will not be personally liable for any unauthorised transactions provided the customer is not responsible for the unauthorised transaction.

In early June, Westpac blamed "human error" when its online banking systems were unavailable for several hours.

Just one week later, the bank's online bank, ATMs and EFTPOS services were crippled by a massive DoS attack.

At the time, Westpac spokesperson David Lording said: "Westpac firewalls were not breached and no fraud was committed ... it caused short term inconvenience to customers who could not access Internet banking".